Are we actually taking about 'locks that tap to 5% health? Because it seems all of those that say they wouldn't heal a 'lock also mention this proviso.
The OPs situ was one where his abilities had not even been demonstrated, and the healer had a blanket policy regardless of the 'lock play-style.
From a lock player, my opinion of one that drops themselves to 5% health, that even *needs* to do that is not a good 'lock.